An example of a conventional refrigerant leak detector of a refrigeration apparatus is disclosed in Japanese Patent Application Publication No. H11-211292. In this refrigerant leak detector, a condensation refrigerant temperature and an evaporative refrigerant temperature are keep at a fixed value by using condensation refrigerant temperature adjustment means and evaporative refrigerant temperature adjustment means, and a refrigerant leak detection operation for detecting refrigerant leaks in a refrigerating cycle is carried out using temperature difference calculation means for comparing output signals of a discharge refrigerant temperature detector and set values and calculating a temperature difference. Therefore, the temperature of the condensation refrigerant that flows through a condenser and the temperature of the evaporative refrigerant that flow through an evaporator are kept at a fixed value, whereby the discharge refrigerant temperature under a suitable refrigerant quantity is set to the set value. The set value and the output signal of the discharge refrigerant temperature detector are compared, a judgment is made that a refrigerant leak has not occurred when the value is less than the set value, and a judgment is made that a refrigerant leak has occurred when the value is higher than the set value.